Process for manufacturing 104-106 r.o.n. leaded gasoline



Oct. 10, 1961 w. w. HAMILTON PROCESS FOR MANUFACTURING 104-106 R.O.N. LEADED GASOLINE Filed June l0, 1959 INVENTOR Qt: .EJ

LVZIESNOSI AVJ States The present invention relates to the production of gasoline having a leaded octane number of 104-106 and more particularly, to a method of fractionating a C4 to 450 P. fraction, preferably a C., to 380 `F. fraction of straight run gasoline, to isomerize the normal C and C6 paraiinic hydrocarbons, reform the C, and higher hydrocarbons, and alkylate the isobutane produced with C3 and C4 olefins from other processes to produce a gasoline containing less than 4 to 7 percent normal paraffms and having a leaded octane number (research +3 cc. TEL) of 104-l06 or more.

Broadly, the present invention provides for fractionatmg a C4 to 450 F. end point fraction, preferably a C4 to 380 F. end point fraction, of straight run gasoline to take overhead a C., and lighter fraction, to take as a side stream a C5 and C6 fraction and to take las a bottoms product a Cs-lfraction. The C5 and C6 Afraction is isomerized to produce a product containing less than 8 percent by volume and preferably less than 4 percent by volume of normal paralinic hydrocarbons. The C6| fraction is reformed to produce a product containing not more than percent by volume and preferably less than 5 percent by volume of normal and isoparaflins. Preferably, -the C3 and C4 hydrocarbons are separated from the reformer product. The C4 hydrocarbons go to an alkylation unit where the isobutane is alkylated with lightV olefins produced by other operations, such as cracking. The normal butane from the alkylation unit is blended into the finished gasoline to provide the required Reid vapor pressure.

Illustrative of the operations whereby gasoline having a le-aded octane number of 104-106 can be made from the C4 to 450 F., preferably 380 F. end point fraction of straight run gasoline is the treatment set forth in a highly diagrammatic manner in the drawing.

The initial feed is a gasoline fraction containing at least C5, `C., and C7 hydrocarbons and boiling up to 450 F., preferably 380 F. A substantial proportion of such a feed isA parainic hydrocarbons.

The gasoline fraction, boiling range C4 to 450 F., preferably C., to 380 F., preferably containing not more than innocuous amounts of sulfur, nitrogen, arsenic and the like, flows from a source not shown through conduit 1 to the suction side of pump 2. `Pump 2 discharges the gasoline fraction into pipe 3 through which the gasoline fraction flows to fractionator 4. In fractionator 4, the gasoline fraction is separated at least into an overhead comprising C., and lighter hydrocarbons, a side stream comprising normal and isomeric C5 and C6 hydrocarbons, and a bottoms product comprising C6 and heavier hydrocarbons. The overhead, C4 and lighter hydrocarbons, flows from fractionator 4 through pipe 5 to conduit 6. The side stream comprising normal and isomeric C5 and C6 hydrocarbons flows from fractionator 4 through pipe 7 to pipe 8. The bottoms product flows from fractionator 4 through pipe 9 to the reforming unit 10. I

When the bottoms product contains innocuous amounts of catalyst poisons such as nitrogen and arsenic, and contains not more than about 20 ppm. (parts per million) of sulfur, i.e., insutlcient sulfur to require the use of highly corrosion-resistant alloy piping and reactor lining, the reforming unit comprises one or more reforming reactors employed in accordance with static bed, moving bed, or fluidized bed technique, reforming catalyst of a char= arent acter and quantity to provide a reformate the C6 and heavier hydrocarbons of which have the target leaded octane rating of at least 104, suitable heaters, means for separating C4 and heavier hydrocarbonfrom hydrogen and C3 and lighter hydrocarbons for use as recycle gas, and a recycle gas compressor for returning tothe reforming reactor or reactors the aforesaid recycle gas. On the other hand, when the bottoms product contains more than innocuous amounts of sulfur, nitrogen, arsenic and the. like provision must be made to reduce the noxous concentrations of these elements to innocuous concentrations. Thus, for example, when the reforming catalyst comprises a metal of the platinum group on an alumina support the bottoms product feed to the reformer unit is treated to remove all but innocuous amounts of these elements usually by hydrogenation of the bottoms product to provide a treated bottoms product containing not more than about l ppm. of nitrogen and essentially free of arsenic and lead. (Essentially free of arsenic and lead designates concentrations cf arsenic and/ or leadsuch that when said treated bottoms is contacted with -a bed of reforming catalyst containing 0.35 percent platinum by weight the catalyst is not deactivated within the life of the catalyst, for example two years, as determined by other factors such as the temperature required to produce a reformate having an octane rating of at least (R.-|3 cc.), the yield of reformate andthe mechanical strength of the catalyst.)

The bottoms product is reformed in reforming unit 10 in the presence of reforming catalyst to produce a reformate having a leaded octane number of at least 104. The C4 and heavier hydrocarbons of the reformed bottoms product flow from the reforming unit through conduit 1l to fractionator 12. In fractionator 12 the reformed bottoms product is fractionated at least into an overhead comprising C3 and lighter hydrocarbons, a side stream comprising C., and lighter hydrocarbons, and a bottoms comprising C5 and heavier hydrocarbons.

'Ihe overhead, C3 and lighter hydrocarbons, flows from fractionator 12 through pipe 13 to the refinery fuel main. The side stream comprising C., and lighter hydrocarbons flows through conduit -14 to conduit 6. The bottoms of fractionator 12, C5 and heavier hydrocarbons, ows through conduit 15 to fractionator 16.

In fractionator 16 the C5 and heavier bottoms of fractionator .12 is separated into `an overhead comprising C5 Vand Cf, hydrocarbons, a side stream comprising substantially pure C6 and heavier 4aromatic hydrocarbons boiling below about 450 F. and preferably boiling below about 380 F., and a bottoms product comprising hydrocarbons boiling above the gasoline range, i.e., above about 380 F. to about 450 F.

The overhead of fractionator 16 flows through pipe 17 to pipe 8. The side stream comprising substantially pure C6 and heavier aromatic hydrocarbons boiling below about 380 F. to about 450 F. flows through conduit 18 to means for admixing additives such as anti-knock material, anti-icing material, anti-rusting material, etc. and storage and/or distribution.

Returning now to the side stream comprising C5 and C6 normal and isomeric hydrocarbons taken from fractionator 4 through pipe 7, it will be observed that the flow sheet provides for mixing the aforesaid side stream, and an isomerizate (obtained as hereinafter described), and the overhead from fractionator .16 in conduit 8. The mixture of side stream, overhead and isomerizate flows through conduit 8 to fractionator 19. In fractionator =19 the mixture of side stream, overhead `and isomerizate is separated at least into an overhead comprising mainly iso-C5 hydrocarbons, a first side stream comprising mainf 1y norm-al pentane, a second side stream comprising iso-Ce hydrocarbons and a bottoms product comprising normal Patented Oct. 10, 1961L hexane through plus some isohexanes. The overhead comprising iso-C5 hydrocarbons ilows from fractionator 19 through pipe 20. The first side stream comprising nor mal pentane flows from fractionator 19 through conduit 21. The second side stream comprising iso-C6 hydrocarbons flows from fractionator 19 through conduit 22. The bottoms product comprising normal hexane iiows from fractionator 19 through pipe 23. The iso-C5 hydrocarbons flow through pipe 20 to conduit 22 where the iso-C5 hydrocarbons mix with the iso-C5 hydrocarbons flowing from fractionator 19 through conduit 22. The mixture of iso-C5 and iso-C6 hydrocarbons flows through pipe 22 to pipe 18 where the Iiso-C5 and iso-C6 hydrocarbons mix with the side stream of fractionator 16 comprising substantially pure C@ and heavier hydrocarbons having an end boiling point Within the range 380 F. to 450 F. The bottoms product comprising normal hexane plus some isohexanes flows from fractionator 19 through conduit 23 to pipe 21 Where the bottoms product mixes with the first side stream comprising normal pentane. The mixed first side stream and bottoms product, now designated isomer feed, ows through conduit 21 to the isomerizing unit 24.

In the isomerizing unit the isomer feed is isomerized in the presence of a suitable isomerizing catalyst such as aluminum chloride or a solid isomerizing catalyst such as one of the platinum metal type. The isomerizate flows from the isomerizing unit 24 through conduit 25 to pipe 8 where, as stated hereinbefore, the isomerizate mixes with the side stream from fractionator 4 owing through conduit 7 and the overhead from fractionator 16 flowing therefrom through pipe A17.

The C4 and lighter overhead flowing from fractionator 12 through pipe 14 yand the C4 and lighter overhead flowing from fractionator 4 through pipe 5 mix in conduit 6 and ow therethrough to fractionator 26. In fractionator 26 at least an overhead comprising C3 and lighter hydrocarbons and a bottoms product comprising C4 hydrocarbon are separated. The overhead comprising C3 and lighter hydrocarbons flows from fractionator 26 through conduit 27 to the reiinery fuel main. The C4 -is taken through conduit 28 to alkylation unit 30. Part or all of the normal butane from the alkylation unit flows through pipe 29 to means for mixing the normal butane with the blend of fractionator 16 side stream owing through conduit 18 in admixture with the iso-C5 and iso-C6 hydrocarbons flowing to conduit 18 through pipe 22 and the alkylate flowing from alkylating unit 30 through conduit 34 (as described hereinafter) to provide the blend `having a leaded octane rating of at least about 104 to about 106 or more.

In alkylation unit 30 the isobutane is alkylated with olens obtained from any suitable source such as a thermal or -a catalytic cracking operation. The alkylation unit can be of any suitable type such as, for example, a thermal alkylation unit or an acid alkylation unit employing sulfuric acid, hydrogen fluoride, etc. Thus, the C4 hydrocarbons flow from fractionator 26 through conduit 28. Olens from a source not shown flow through pipe 31 to the suctiton side of pump 32. Pump 32 discharges the olens into conduit 33 through which the olens flow to the alkylation unit 30. The alkylate flows from alkylation unit 30 through pipe 34 to pipe 18 Where it mixes with the substantially pure aromatic C6 and heavier hydrocarbons, the iso-C5 and iso-C6 hydrocarbons and the normal butane to provide a gasoline blend having the target Reid vapor pressure and a leaded octane rating of at least 104-106.

In the reforming unit the fractionator bottoms or the decontaminated fractionator bottoms are reformed in the presence of an aromatization type catalyst under a severity of conditions of temperature, pressure, hydrogen to bottoms ratio and space velocity to insure conversion of substantially all of the C64- hydrocarbons to aromatics. A suitable aromatizing catalyst of the platinum type comprises about 0.3 to about 1.0 percent, by weight, platinum, on a support such as alumina or alumina and silica. Suitable aromatizing conditions to convert substantially all of the CS-lhydrocarbons to aromatics employing a platinum-type catalyst are a temperature within the range about 850 F. to about 1000 F., a pressure within the range about 200 to about 600 p.s.i.g., a hydrogen to bottoms mol ratio of about 4 to 20 and a liquid space velocity of about 0.2 to about 2.0 volume of bottoms per volume of catalyst per hour (v./v./hr.). Wnen employing an aromatizing reforming catalyst comprising the oxide of one or more metals of group Vl of the periodic table on alumina as a suport, e.g., 18 to 20 Weight percent chromium oxide on alumina, the reaction conditions to convert substantially all of the hydrocarbons of the CG-lfraction to aromatic hydrocarbons are a temperature Within the range of about 900 F. to about 1100 F., a pressure within the range of about 100 to about 500 p.s.i.g., a space velocity of Iabout 0.2 to about 1.5 v./hr./v., and a hydrogen to naphtha mol ratio of about 2 to about 10.

When the feed to fractionator 4 has an end point of about 380 F. to 390 F. the side stream in fractionator 16 is substantially pure aromatic hydrocarbons boiling below about 430 F. and is the aromatic fraction of the gasoline having a leaded octane number of 104-106. This side stream product has a leaded octane number of about 114. 1n this case, there is no bottoms product from frac tionator 16. However, when the feed to fractionator 4 has an end point substantially above 380 F. to 390 F. say 400 F. or higher, it is necessary to separate the pure aromatic hydrocarbons boiling in the gasoline range from hydrocarbons boiling above the gasoline range. Such a situation is illustrated in the drawing. Thus, when the feed to fractionator 4 has an end point substantially above 390 F. a substantially pure aromatic hydrocarbon fraction comprising C6 and Cs-I- aromatic hydrocarbons is taken as a side stream through pipe 18 to blending to produce with the alkylate, the isomerized C5 and C6 hydrocarbons, and the butanes necessary to produce the required volatility and Reid vapor pressure a gasoline having a leaded octane number of 104-106 or more (research-H cc. rTIEL). The higher boiling aromatic hydrocarbons, i.e., boiling above about 430 F., are taken as a bottoms product from fractionator 16 through pipe 40 to storage for use as such, for dealkylation or the like.

It is to be noted that the ultimate product from the isomerization unit contains less than 8 percent and preferably less than 4 percent by volume normal parans. The ultimate product from the reforming unit (pipe 18) contains not more than ten percent and preferably less than 5 percent, by volume, of parains of any type including isoparains. The ultimate product before presuring with normal butane comprises about 4 to about 7 percent by volume of normal parans, about 30 to about 40 percent by volume of isoparalins, about 50 to about 60 percent by volume aromatics and has a leaded octane number of 104-106 or more (research +3 cc. TEL).

I claim:

1. A method of producing gasoline having a leaded octane number of at least 104-106 (research +3 cc. TEL) which comprises fractionating a Crand heavier fraction or naphtha having an end boiling point not greater than 450 F. to provide a rst fraction compris ing C4 and lighter hydrocarbons, a second fraction comprising C5 to C8 hydrocarbons, and a third fraction comprising hydrocarbons heavier than C8 hydrocarbons, reforming the aforesaid third fraction in the presence of hydrogen and an aromatizing reforming catalyst under reforming conditions of temperature, pressure, and space velocity to convert substatnially all of the hydrocarbons in the aforesaid third fraction to aromatic hydrocarbons and C5 and lighter parainic hydrocarbons to obtain a reformer eflluent comprising hydrogen and C1 and heavier hydrocarbons, separating the aforesaid reformer effluent into recycle gas comprising hydrogen and C1 and C2 hydrocarbons, a fourth fraction comprising C3 yand lighter hydrocarbons, a fth fraction comprising C4 and lighter hydrocarbons, a sixth fraction comprising C5 and C6 hyydrocarbons, a seventh fraction comprising substantially pure aromatic hydrocarbons containing not more than lO percent by volume of paraflins and having an end boiling point of about 380 to 430 F., and an eighth fraction comprising hydrocarbons boiling above about 380 to 430 F., isomerizing all of the aforesaid C5 and C6 'actions comprising the aforesaid second fraction and the aforesaid sixth fraction to produce an ultimate isomerized product (P) containing less than 8 percent by volume of normal paraflins, fractionating the aforesaid first fraction and the aforesaid fth fraction to obtain -a ninth fraction comprising nand iso-C4 hydrocarbons, alkylating the iso-C4 hydrocarbons in the aforesaid ninth fraction with olens to obtain an alkylate, mixing said alkylate, the aforesaid ultimate isomerized product containing less than 8 percent by volume of normal paraus, the aforesaid seventh fraction comprising substantially pure aromatics containing not more than 10 percent by volume of paraiins, and normal C4 hydrocarbons obtained fromthe -aforesaid alkylation of iso-C4 hydrocarbons in amount to provide the required volatility and vapor pressure to produce a gasoline blend having a leaded oct-ane number of at least 104 (research |3 cc. TEL).

2. The method of producing gasoline having a leaded octane number of 104 to 106 (research +3 cc. TEL) Ias set forth and described in claim 1 wherein the C4 and heavier fraction of naphtha has an end boiling point not greater than about 390 F., -and the gasoline blend before pressuring with n-C4 hydrocarbon comprises about 4 to 7 percent by volume of normal parains, about 30 to percent by volume of isoparains, yand about 50 to percent by volume aromatics.

References Cited in the le of this patent UNITED STATES PATENTS 2,276,171 Ewell Mar. 10, 1942 2,372,711 Cornforth .Apr- 3, 1945 v2,376,077 Oberfell et al. May 15, 1945 2,443,607 Evering June 22, 1948 2,905,619 Sutherland Sept. 22, 1959 

1. A METHOD OF PRODUCING GASOLINE HAVING A LEADED OCTANE NUMBER OF AT LEAST 104-106 (RESEARCH +3 CC. TEL) WHICH COMPRISES FRACTIONATING A C4 AND HEAVIER FRACTION OR NAPHTHA HAVING AN END BOILING POINT NOT GREATER THAN 450*F. TO PROVIDE A FIRST FRACTION COMPRISING C4 AND LIGHTER HYDROCARBONS, A SECOND FRACTION COMPRISING HYDROCARBONS, AND A THIRD FRACTION COMPRISING HYDROCARBONS HEAVIER THAN C6 HYDROCARBONS, REFORMING THE AFORESAID THIRD FRACTION IN THE PRESENCE OF HYDROGEN AND AROMATIZING REFORMING CATALYST UNDER REFORMING CONDITIONS OF TEMPERATURE, PRESSURE, AND SPACE VELOCITY TO CONVERT SUBSTANTIALLY ALL OF THE HYDROCARBONS IN THE AFORESAID THIRD FRACTION TO AROMATIC HYDROCARBONS AND C6 AND LIGHTER PARAFFINIC HYDROCARBONS TO OBTAIN A REFORMER EFFLUENT COMPRISING HYDROGEN AND C1 AND HEAVER HYDROCARBONS, SEPARATING THE AFORESAID REFORMER EFFLUENT INTO RECYCLE GAS COMPRISING HYDROGEN AND C1 AND C2 HYDROCARBONS, A FOURTH FRACTION COMPRISING C3 AND LIGHTER HYDROCARBONS, A FIFTH FRACTION COMPRISING C4 AND LIGHTER HYDROCARBONS, A SIXTH FRACTION COMPRISING C5 AND C6 HYDROCARBONS, A SEVENTH FRACTION COMPRISING SUBSTANTIALLY PURE AROMATIC HYDROCARBONS CONTAINING NOT MORE THAN 10 PERCENT BY VOLUME OF PARAFFINS AND HAVING AN END BOILING POINT OF ABOUT 380* TO 430*F., AND AN EIGHTH FRACTION COMPRISING HYDROCARBONS BOILING ABOVE ABOUT 380* TO 430*F., ISOMERIZING ALL OF THE AFORESAID C5 AND C6 FRACTIONS COMPRISING THE AFORESAID SECOND FRACTION AND THE AFORESAID SIXTH FRACTION TO PRODUCE AN ULTIMATE ISOMERIZED PRODUCT (P) CONTAINING LESS THAN 8 PERCENT BY VOLUME OF NORMAL PARAFFINS, FRACTIONATING THE AFORESAID FIRST FRACTION AND THE FORESAID FIFTH FRACTION TO OBTAIN A NINTH FRACTION COMPRISING N- AND ISO-C4 HYDROCARBONS, ALKALATING THE ISO-C4 HYDROCARBONS IN THE AFORESAID NINTH FRACTION WITH OLEFINS TO OBTAIN IN ALKYLATE, MIXING SAID ALKYLATE, THE AFORESAID ULTIMATE ISOMERIZED PRODUCT CONTAINING LESS THAN 8 PERCENT BY VOLUME OF NORMAL PARAFFINS, THE FORESAID SEVENTH FRACTION COMPRISING SUBSTANTIALLY PURE AROMATICS CONTAINING NOT MORE THAN 10 PERCENT BY VOLUME OF PARAFFINS, AND NORMAL C4 HYDROCARBONS OBTAINED FROM THE AFORESAID ALKYLATION OF ISO-C4 HYDROCARBONS IN AMOUNT TO PROVIDE THE REQUIRED VOLATILITY AND VAPOR PRESSURE TO PRODUCE A GASOLINE BLEND HAVING A LEADED OCTANE NUMBER OF AT LEAST 104 (RESEARCH +3 CC. TEL). 